The present invention is directed to a microprocessor-based sensor for detecting the presence of snow upon a sensing surface and providing an output as to snow presence.
Preventative safety and automatic snow removal systems require an immediate indication when snow is beginning to accumulate on a monitored surface. To efficiently implement such systems a reliable snow sensor is required so that system elements are not unnecessarily operated. Some applications for the snow sensor of the present invention is used where snow detection triggers automatic snow removal from surfaces such as railways, roadways, bridges, pedestrian walkways and the like.
Further applications of the snow sensor include situations where manual intervention is required. A reliable snow sensor must provide an indication of the presence of snow so that necessary and adequate weather precautions will be prepared in advance of significant snow accumulation. A suitable alarm or warning coupled to the snow sensor signal will be effective to alert persons to take action in this situation.
Prior art snow sensors use a variety of methods for sensing the presence of snow. Some prior art approaches to sensing snow utilize optical, microwave or electromagnetic means. Other prior art sensors employ vibration analysis and still others use electrical measurements of resistivity or capacitance, which vary with the presence of ice and snow. Many of the prior art snow sensors rely on snow or ice accumulation to occur before a positive snow signal is emitted.
Prior art snow and ice sensor systems abound in the aerospace industry. However, the majority of aerospace snow sensors rely on a moving airmass to generate ice formation. Others sample a moving airmass for liquid water content, temperature and humidity. In some aerospace snow sensors heating means are used to cause accumulated snow or ice to be shed from the sensor to provide dynamic snow and ice sensing capability.
A need continues to exist for a simple, reliable and accurate snow sensor for detecting minute amounts of snow accumulation without relying on a moving airmass or coordinated weather measurements.